Electromagnetic relay



Nov. 4, 1941. woo 2,261,818

ELECTROMAGNETIC RELAY Filed June 15, 1939 I195 u/afion INVENTOR.

Fredric E. Wood BY ATTORNEYS Patented Nov. 4, 1941 2,261,818ELECTROMAGNETIC RELAY Fredric E. 'Wood, on Park, 111., assignor toAssociated Electric Laboratories, Inc., Chicago, 11]., a corporation ofDelaware Application June 15, 1939, Serial No. 279,315

1 Claim.

The present invention relates to electromagnetic devices andmoreparticularly to electromagnetic relays of the switching type.

An electromagnetic relay conventionally comprises a field structureincluding a core provided with a winding, a movable armature carried bythe field structure, and a set of switch springs operatively connectedto the armature.

It is an object of the present invention to provide an improved relay ofthe type described, which is of rugged and economical construction andwhich is reliable and positive in operation.

Another objectof the invention is to provide, in a relay of the typedescribed, an improved arrangement for pivotally mounting the armatureon the fleldstructure and for locking the armature in place. I c

In brief, the objects set forth above are in part realized inaccordance. with one feature of the present invention by providing anelectromagnetic relay comprising a longitudinally extending core, asubstantially L-shaped field element including a first laterally andforwardly extending leg secured to one end of the core and a secondlongitudinally extending leg arranged in spacedapart relation withrespect to the core, and an armature. An arrangement including integrallugsprovided on the outer end of the secondleg of the field element andcooperating openings provided in the armature adjacent the inner endthereof is utilized for pivotally mounting the armature on the outer endof the second leg and.

. in cooperating relationship with respect to the outer end of the core,'Further,=a substantially L-shaped bracket is provided which includes afirst longitudinally extending arm secured to the second leg of thefield element and a second laterally and rearwardly extending arm. Alaterally and forwardly extending projection is carried by the secondarm of the bracket which engages the ends of the lugs provided'on theouter end of the second leg of the field element, thereby to lock thearmature in place on the outer end of the second leg. Further the secondarm of the bracket carries a spring which engages the amiature in orderto urge the armature in seated enj gagement withthe outer end of thesecond leg of the field element.and a stop for limiting the pivotalmovement of the armature away from the outer'end of the core. Finally,the second arm carried thereby comprises a link formed of a suitableinsulating material. The armature is connected to the link by anarrangement including an integral lug provided on the outer end of thearmature and a cooperating opening provided in the link, the lugprojecting through the cooperating opening and extending inwardly toprovide an inwardly directed seat arranged to receive and engage thewall of the link adjacent the cooperating opening. Similarly, one of theswitch springs of the set of switch springs is connected 7 to the. linkby an arrangement including an integral lug provided on the outer end'ofthe switch spring and a cooperating opening provided in the link, thelug projecting through the cooperating opening and carrying outwardlyextending spaced-apart fingers to provide an outwardly directed seatarranged to receive and engage the wall of thelink adjacent thecooperating opening.

Finally the lugs respectively provided on the outer end of thearmatureand on the outer end of the switch spring and the respectivecooperating openings provided in the link are so constructed andarranged that they are readily engageable and disengageable, thereby tofacilitate ready placement and removal of the link.

Further features of the invention pertain to the I particularconstruction and arrangement of the elements of the relay whereby theabove-outlined and additional operating features are attained.

The novel features believed to be characteristic of the invention areset forth with particularity,

in the appended claim. The invention, both as to its organization andmethod of operation, to-

gether with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconnection with the accompanying drawing, in which Figure 1 is a planview of an electromagnetic relay constructed and arranged in accordancewith the present invention; Fig. 2 is a longitudinal sectional view ofthe relay taken along the line 2-2 in Fig. 1; Fig. 3 is an endelevational view of the relay shown in Fig. 1; and F lg. 4 is afragmentary exploded perspective view of the relay illustrating themounting arrangement for the armature thereof.

Referring now more particularly to Figs. 1 to 3, inclusive, of thedrawing, the electromagnetic relay there shown comprises a fieldstructur including a longitudinally extending core l0 provided with awinding H and a substantially L- shaped field element i2 including afirst laterally and forwardly extending leg l3 secured to .one' end ofthe core HI by a screw l4, extending through an opening provided in theleg l3 and threaded into a tapped hole provided in the end of the coreID, and a second longitudinally ex tending leg l5 arranged inspaced-apart relationship with respect to the core Ill. The winding Hsurrounds the core Ill and is retained in place by a pair-ofspaced-apart retaining heads l6 and I1 arranged on the opposite ends ofthe winding II and surrounding the core ID, th retaining heads l6 and I!being formed of a suitable insulating material.

Also the relay comprises a movable armature l8 and a substantiallyL-shaped bracket IS including a first longitudinally extending arm 20and a second laterally and rearwardly extending arm 2|. As best shown inFigs. 2 and 4 of the drawing, the inner end of the armature I8 ispivotally mounted on the outer end of the leg l5 intervening strips 34of a suitable insulating and the arm is secured to the leg |5 by twoscrews 22 extending through openings provided in the arm 20 and threadedinto tapped holes provided in th leg l5. The arrangement for pivotallymounting the inner end of the armature IS on the outer end of the leg l5comprises interfitting lugs respectively carried on the outer end of theleg |5 and on the inner end of the armature I8. Specifically, theintermediate portion of the outer end of the leg I5 is cut out toprovide two lugs 23 spaced apart by an intervening notch 24; while theopposite sides of the armature l8 adjacent the inner end thereof are cutout to provide two spaced-apart lugs 25 and associated spaced-apartnotches 26. Also the intermediate portion of the inner end of thearmature I8 is cut out to provide a notch 21 disposed intermediate thetwo spaced-apart lugs 25. When the field element l2, the armature I8 andthe bracket H are in assembled relationship the two spaced-apart lugs 23provided on the leg I! extend into and project through the twospacedapart notches 26 provided in the armature l8; andthe intermediateportion of the armature I8 is disposed in the notch 24 provided in theleg l5. Furthermore, the notch 21 provided in the armature l8 receivesthe leg 20.

The order to lock the inner end of the armature IS in place on the outerend of the leg IS, an arrangement is provided which comprises twospaced-apart laterally and forwardly extending projections 29 carried bythe arm 2| of the bracket I9. More particularly, the two spacedapartprojections 29 carried by the arm 2| of the bracket l9 overlie anddirectly engage the ends of the two spaced-apart lugs 23 carried by theleg l5 of the field element l2. This arrangement positively locks theinner end of the armature IS in place on the outer end of the leg l5;yet, it provides for'ready removal or the armature I8. This may beaccomplished merely by unthreading the screws 22 from th tapped holesprovided in the leg |5 and then removing the bracket l3, whereupon theinner end of the armature l3 may be removed from the outer end of theleg IS in an obvious manner.

In addition to providing an arrangement for locking the inner end of thearmature IS on the outer end of the leg IS, the arm 2| of the bracket l9carries a leaf spring 30, a stop 3|, a set of switch springs 32 and aclamping plate 33 in stacked relationship. Specifically, the leaf spring30 is arranged directly upon the arm 2|, the stop 3| is arranged uponthe leaf spring 30, and the switch springs of the set of switch springs32 are separated from each other and from the stop 3| and the clampingplate 33 by material. Finally the clamping plate 33, the switch springsof the set of switch springs 32, the strips 34 of insulating material,the stop 3|, and the leaf spring 30 are retained in assembled andstacked relationship by twoscrews 35 extending through aligned openingsprovided therein and threaded into tapped holes provided in the arm 2|.The set of switch springs 32 is illustrated as comprising two switchsprings 35 and 31, although it will be understood that the set of switchsprings 32 may comprise any reasonable number of switch springs.Furthermore, it is noted that the arm 2| of the bracket H has two setsof spaced-apart openings 2|a and 2| 1) provided therein which aredisposed on opposite sides of the set of switch springs 32, these twosets of openings being arranged to fasten two additional sets of switchsprings to the arm 2| or to fasten the arm 2| on a suitable support, asdesired. When the two sets of opening 2| a and 2|b provided in the arm2| of the bracket l9 are utilized to fasten the arm 2| to a support, theentire weight of the relay is supported by the arm 2|. Th switch springs36 and 31 are respectively provided with terminals 36a and 37a to whichelectrical connections may be extended, and carry cooperating contactsadjacent the outer ends thereof, which are arranged in switchingrelationship and preferably formed of a suitable precious metal.

The leaf spring 30 is provided with an outwardly projecting and inwardlycurved end 30a arranged in direct engagement with the inner end of thearmature l8, thereby to urge the inner end of the armature l8 intoseated engagement with the outer end of the leg I5 and to preventlongitudinal movement therebetween incident to the pivotal movement ofthe armature l8 away fromthe cooperating outer end of the core HI. Alsothe stop 3| is provided with an outwardly projecting and inwardlydirected end 3|a which cooperates with the armature l8 to limit thepivotal movement of the armature l8 away from the outer end of the coreI. Furthermore, the armature II has an opening provided therein, intowhich a rivet, 33 formed of nonmagnetic material is securely fastened,the rivet 33 being arranged to engage the outer end of the core Ill whenthe armature I3 is moved toward the core Ill, The arrangement of therivet 33 carried by the armature 8 with respect to the outer end of thecore I prevents the armature I8 from sticking to the outer end of thecore I0 when the armature I8 is moved toward the outer end of the coreincident to the energization of the winding In order operatively toconnect the armature l8 and .the movable switch spring 36 of the set ofswitch springs 32, an arrangement is provided which comprises a link 33formed of a suitable insulating material. More particularly, the link 39has a pair of spaced-apart openings 40 formed therein adjacent the innerend thereof and a centrally disposed opening 4| formed therein ad-.jacent the outer end thereof, the opening 4| being arrangedintermediate and in spaced-apart relationship with respect to the twoopenings 40. Two integral lugs 42 are provided on the outer end of thearmature |3, these lugs being arranged to project through thecooperating openings 40 provided in the link 33. Similarly, an integrallug 43 is provided on the outer end of the switch spring 36, this lugbeing arranged to project through the cooperating opening 4| prospring36 carries integral and outwardlylextending spaced-apart fingers 44which provide an outwardly directed seat arranged to receive and engagethe wall of the link 39, adjacent the opening provided therein.

The lugs 42 provided on the outer end of the armature It, the lug 43provided on the outer end of the switch spring 33, and the cooperatingopenings 49 and 4| provided inthe link 39 are so constructed andarranged that they are readily engageable and disengageable; thereby toiacilitate ready placement and removal of the link 39. Moreparticularly, the link 39 may be readily removed by forcing the switchspring 36 inwardly, thereby to disengage the outwardly directed seatprovided in the lug 43 and the associated wall of the link 39 adjacentthe cooperating opening 4|, and then by swinging the link 39 away fromthe switch spring 33. The inwardly directed seats provided in the lugs42 and the. associated walls of the link 39 adjacent the cooperatingopenings 40 may then be disengaged, in an obvious manner, in order topermit the link 39 to assembly.

Furthermore, it is noted that two spaced-apart slots 45 are provided onthe opposite sides of the link 39 adjacent the outer end thereof, theseslots being arranged to accommodate the two-cobe completely removed fromthe v operating lugs provided on the two switch springs of the two setsof switch springs, in the event the relay comprises three sets of switchsprings,

as previously noted, More particularly, the two sets of switch springs,which may be secured to the arm 2| of the bracket H! by utilizing thetwo sets of aligned openings 2-la and 2|b formed in the arm 2|, may beoperatively connected to the link 39 by utilizing the slots 49 providedtherein, in the manner previously explained.

In assembling the relay, the leg ll of the field element I2 is firstsecured to the core ID with the screw l4, and the winding II is thenplaced upon the core l0. Subsequently, the inner end of the armature I8is positioned on the outer end of the leg l5 of the field element l2,and

.the bracket I9 is secured in place, thereby to lock the inner end ofthe armature ll upon the outer end of the leg I5. Thereafter, the leafspring 30, the stop 3|, the set of switch springs 32, the insulatingstrips 34 and the clamping plate 33 are assembled upon the arm 2| of thebracket l9 in an obvious manner, the engagement. between the outer end30a of the leaf spring 30 and the inner end of the armature l3 retainingthe inner end of the armature II in seated engagement with the outer endof the leg it. Finally, the armature I3 is operatively connected to theswitch spring 33 by placing the link 39 in its cooperating position withrespect to the lugs 42 and 43 respectively provi ed on the outer ends ofthe armature l3 and spring 33'.

Normally the switch spring 33 exerts a force e switch the winding II isenergized, the magnetic flux traversing the core III, the fleld elementl2 and the armature |8 causes the armature I! to be moved toward theouter end of the core ill, the inner end of the armature l8 beingpivoted in a clockwise direction, as viewed in Fig. 2, about the outerend of the leg I! of the field element l2. This movement of the armaturel8 toward-the outer end of the core I9 is transmitted by the link 39 tothe switch spring 36, in order to cause the contacts carried by "theswitch springs 38 and 3'! to be moved into engagement; When the windingH is deenergized the switch spring 33 then moves the armature ll awayfrom the outer end of the core It, the inner end of the armature I8being pivoted in a counterclockwise direction, as viewedin' Fig. 2.about the outer end of the leg ii of the field element l2. When theswitch. spring 33 returns .to its normal position the set ofcontactscarried by the switch springs 38 and 31 are moved into disengagement.Accordingly,

the movement of the armature I9 is controlled Jointly by theenergization of the winding l I and 'the resiliency of the switch spring38; and the armature is prevented from sticking to the outer end of thecore l9 due to any residual magnetism in the core I. by the rivet 33formed of nonmagnetic material.

In view of the foregoing it is apparent that an improved electromagneticswitching relay is provided which is of rugged andeconomicalconstruction and which is reliable and positive in operation.

While there has been described what isat present considered to be thepreferred embodiment of the invention, it will be understood thatvarious modifications may be made therein, and it is intended tocoverrin the appended claim all such modifications as fall withinthe'true' integral lugs provided on the outer end of said through thelink 33 upon the outer end the armature I3, thereby to restrain thearmature l3 away from the outer end of the core II and toward the outerend an; of the stop a. when second leg and cooperating openings providedin said armature adjacent the inner end thereof for pivotally mountingthe inner end of said armature on the outer end of said second leg andincooperating relationship with respect to the outer end of said core, asubstantially L-shaped bracket Y including a first longitudinallyextending arm removably secured to said second leg and a secondlaterally and rearwardly extending arm, means including a laterally andforwardly extending projection carried by said second arm and engagingthe ends of said lugs for locking the inner end of said armature inplace on the outer end of said second leg, means including a leaf springcarried by said second arm and pro- Jecting forwardly into engagementwith said armature for urging the inner end of said armature in seatedengagement with'the outer end of said second leg, and means including astop carried by said second arm and projectlng'forwardly over saidarmature for limiting the pivotal movement of said armature away fromthe outer end of said core.

FREDRIC E. WOOD-

